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<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
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<body>
  <script>
    // +
    // -
    // /
    // *
    // %

    // 小数精度有问题 0.1

    console.log( 1 + 2)
    console.log( 1 - 2)
    console.log( 1 * 2)
    console.log( 1 / 2)
    console.log( 1 % 2)
    console.log( 3 % 5 ) // 3
    
    

  </script>
</body>
</html>